Hello, @nathanawesome95! If a song or entire album is unavailable to you it is likely due to the following reasons:
1. It's down to the record label in that they may have limited which regions would have access to the full album or the song you are looking for. In this case Spotify can't really do much about it and there is no estimated time as to when the music should be back in the catalogue.
2. It's a temporary issue. No need to worry as the album should be back in no time.
That's just how the system works.
